1. Field of the Invention
The present invention relates generally to information systems and storage systems.
2. Description of Related Art
A number of factors are significantly increasing the cost of operating data centers and other information processing and storage facilities. These factors include a tremendous increase in the amount of data being stored, rising energy prices, and computers and storage systems that are consuming more electricity and that are requiring greater cooling capacity. If current trends continue, many data centers may soon have insufficient power capacity to meet their needs due to the increasing density of equipment and rapid growth in the scale of the data centers. Therefore, achieving power efficiency is a very critical issue in today's datacenters and other information processing and storage facilities. Related art includes U.S. Pat. No. 7,035,972, entitled “Method and Apparatus for Power-Efficient High-Capacity Scalable Storage System”, to Guha et al., filed Jun. 26, 2003, the entire disclosure of which is incorporated herein by reference.
Also, solutions for addressing the tremendous increase in the amount of data being stored include technologies for reducing this huge amount of data. One such technology is data de-duplication, which is based on the premise that a large amount of the data stored in a particular storage environment already has redundant portions also stored within that same storage environment. During the data writing process, a typical de-duplication function breaks down the data stream into smaller chunks of data and compares the content of each chunk of data to chunks previously stored in the storage environment. If the same chunk of data has already been stored in the storage system, then the storage system just makes a new link to the already-stored data chunk, rather than storing the new data chunk that has same content. Related art includes U.S. Pat. Appl. Pub. No. 2005/0216669, entitled “Efficient Data Storage System”, to Zhu et al., filed May 24, 2005, the entire disclosure of which is incorporated herein by reference, and which teaches a typical method for storing data with a de-duplication function.
Consequently, the use of data de-duplication in a storage environment reduces the overall size of the data stored in the storage environment, and this technology has been adopted in many storage systems, including in VTL (Virtual Tape Library) systems and other systems for performing data backup. Prior art related to VTL systems includes U.S. Pat. No. 5,297,124, to Plotkin et al., entitled “Tape Drive Emulation System for a Disk Drive”, the entire disclosure of which is incorporated herein by reference, and which is directed to a VTL system, namely, a virtual tape backup system that uses a disk drive to emulate tape backup. Using VTL or other data backup systems, it is possible to consolidate all data for backup from a variety of applications, divisions, sources, etc., into a single data backup storage solution that allows single-point management as well. However, because de-duplication technology continuously compares new incoming data chunks with previously-stored data chunks at the volumes of the storage system, these volumes need to be always powered on. This is because any of the previously-stored chunks may need to be compared with a new incoming chunk, and there is no guarantee that a specific portion of the stored data will not be needed for making the comparison over any certain period of time. This situation, while reducing the overall amount of data stored, does little else to aid in reducing the amount of power consumed by the storage system. Accordingly, there is a need for a more power-efficient method for performing data backup while also performing de-duplication of the data being backed up.